Various optical scanning systems and readers have been developed heretofore for reading indicia, such as bar code symbols appearing on a label or on the surface of an article. The bar code symbol itself is a coded pattern of graphic indicia comprised of a series of bars of various widths spaced apart from one another to bound spaces of various widths, the bars and spaces having different light reflecting characteristics. The readers function by electro-optically transforming the spatial pattern represented by the graphic indicia into a time-varying signal, which is in turn decoded into data which represent the information or characters encoded in the indicia that are intended to be descriptive of the article or some characteristic thereof. Such data is typically represented in digital form and utilized as an input to a data processing system for applications in point-of-sale processing, inventory control, distribution, transportation and logistics, and the like. Scanning systems and readers of this general type have been disclosed for example, in U.S. Pat. Nos. 4,251,798; 4,369,361; 4,387,297; 4,409,470; 4,760,248; 4,896,026; 5,015,833; 5,262,627; 5,504,316; 5,625,483; and 6,123,265, all of which have been assigned to the same assignee as the instant application each of which is hereby incorporated by reference herein in its entirety. As disclosed in some of the above patents, in one embodiment such a scanning system resides, inter alia, in a hand-held portable laser scanning device supported by a user, which is configured to allow the user to aim a scanning head of the device, and more particularly, a light beam, at a targeted symbol to be read.
The light source in a laser scanner bar code reader is typically a semiconductor laser. The use of semiconductor devices as the light source is advantageous because of their small size, low cost and low voltage requirements. The laser beam is optically modified, typically by an optical assembly, to form a beam spot of a certain size at the target distance. The laser light beam is directed by a lens or other optical components along a light path toward a target that includes a bar code symbol on the target surface.
Many types of bar code readers, including hand-held readers, have a user feedback feature that gives a visual or audio indication that the scanner has been activated and/or that the decode is successful. This user feedback feature is often an LED that is illuminated to indicate that the beam is activated or that a decode is successful. The LED may be visible to the user through a window in the reader housing or coupled to a light pipe that directs the light to a location outside of the scanner housing. While providing valuable feedback to a reader user, the LED and light pipe add cost and complexity to the reader.